Lovely Runner

ML likes FL first (this one actively chases after her tho) but both really REALLY like her.
Suburban/Small town setting
Same quirky humor
Serial killer after the female lead
Both these shows add some aspects of a thriller in the drama which juxtaposes the bright romantic tone the show presents itself as.
(Both shows are able to still stay light throughout it tho)

Both dramas are about one of the leads suddenly dying and the other time traveling back to their school days in an effort to save their life.

Both dramas are about one of the leads suddenly dying and the other time traveling back to the past in an effort to save their life.

- FL thought she fell first, but it’s the ML who liked her first!
- Good chemistry between the leads

Both FLs time travel to their school days in an effort to save someone.
.............................................................

Both dramas are about one of the leads suddenly dying and the other attempting through time travel to save their life.

Both FLs time travel into the past to save the ML who has died in the present. It's then revealed that the ML was secretly in love with her a long time before she believes they first met.

In both series, he saves the life of one of the characters by time travel.
They have crime, romance and humor.
The character has to go back in time several times.
It takes place in modern times.
A handsome man and a cheerful, lovely girl.

I know these have nothing to do with each other in a sense, but the "time travel" aspect kind of gave me this sense of, if you make the wrong decision someone you love could die. Lovely Runner of course is not a BL, but I found the ending to be more satisfying than 4M.
Also LR has some what if moments to it, while also being a thriller. Not as cinematographic as 4M, but has some comedic moments to make up for that.

Shining for one thing: The movie is a movie while Lovely Runner is a show.
FL travels back in time to save ML.
ML had feelings for the FL from the beginning.
A tragic accident took ML's life.
Everything begins in the school.
Friends turned lovers.

Although they have a different plotline, Kimi ga Kokoro wo Kuretakara reminds me of Lovely Runner in many ways. The same umbrella (although different colors) reference, meeting up when they are older, FL doing the "work" to save ML's life. Those kind of stuff. Anyway, the overall mood of KGKWK is much more melodramatic (despite having many crying scenes in LR too) and there is much more trauma esp in FL end.

In both the dramas FL time travels to past in her high school time.
Both FL has a crush on the male lead .
It's really funny and lovely drama I highly recommend it

in both dramas, the female leads have an injury and are at a low point in their lives when they meet the male lead :)

The ML will fall into a coma, and the FL who wrote the story of the ML who is a character in his book, will enter the space time of his Novel to be able to save him and change his destiny

-time travel
-sorta time loop (ML dies no matter how much the other partner tries to save them)
-butterfly effect (future changes becoz of past actions i.e. there is only one timeline)
-chemistry is good
-romcom

Difference is that Triage a medical drama and shows a more prominent time loop and ML is able to write what happens in each while FL in LR cannot write or say anything about the future to past people.